Screenshot the arena

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description must carry the behavioral disclosure. It states the output is a PNG and captures the current arena, which implies a read-only operation. But it does not disclose how the PNG is returned, whether the action has side effects, or any latency/cost. For a simple no-parameter tool this is adequate but minimal.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, front-loaded sentence: the core action ('Get a PNG screenshot of the current arena') comes first, followed by a brief rationale. No filler or repetition.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a no-parameter visual-read tool, the description covers what it returns (PNG), what it captures (current arena), and why to use it (visual inspection instead of coordinates). The only missing detail is the mechanics of the returned image (e.g., file path, base64, size), which would be useful but is not critical given no output schema.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool has zero parameters and 100% schema coverage, so there is nothing for the description to add beyond confirming the invocation requires no arguments. Baseline of 4 for parameterless tools applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific verb and resource: 'Get a PNG screenshot of the current arena.' It clearly distinguishes from sibling get_state by stating the screenshot lets you 'look at the match instead of only reading coordinates,' so an agent can tell it apart without opening schemas.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies the use case explicitly: use screenshot when you need a visual view of the arena, as opposed to reading coordinates (presumably from get_state). However, it doesn't name alternative tools or provide explicit when-not-to-use guidance, so it falls short of a 5.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.